I agree with your general point about the effects of such rudeness, but I also think the solution is to actually "just" write to these people (in broad cc) and say "Please consider that, although [you] devs were right, [you] could have expressed [your]selves more cordially. I don't think being that rude improves anything, [and] this behaviour has affected my willing to contribute with the project.". Even if your own email falls on deaf ears, the second or third will trigger reflection. And the 10th will trigger some sort of review by colleagues. After all, at the end of the day, it's a team of adults who are all in it for the same goal, and they should be trusted to be able to handle it like adults when concerns have been expressed in the appropriate manner.
Whereas CoC-driven development risks leading to a chilling effect where you no longer constructively argue about stuff, let alone in a passionate manner (that, admittedly, risks going the wrong side of the fence on occasion), and just let shit pile up because it's not your business to be getting the snake out of the hole and messing with a CoC Panel for it.
And this is even in the 'ideal' case where the CoC Panel has no 'political' ulterior motives. God forbid when this is not the case.
Basically, careful what you wish for.